1. Field of the Invention
The present invention relates generally to an apparatus for controllably blending gases. More particularly the invention concerns an apparatus for blending gases such as nitrogen and carbon dioxide for use in connection with beverage dispensing systems of the character wherein beverage contained in a bulk container is controllably dispensed therefrom by admission of the gas mixture under pressure to the container.
2. Discussion of the Prior Art
The use of carbon dioxide gas in the dispensing of beverages such as beer, ale or stout is well known. However, it has been found that for certain applications the use of a mixture of carbon dioxide gas and a second gas, such as nitrogen, provides certain advantages. For example, the use of such a mixture alleviates excessive carbonization of the beverage being dispensed and, when used in dispensing beer, advantageously achieves a stable and creamy head on the beer.
While the advantages of using a gaseous mixture of nitrogen and carbon dioxide in dispensing beer have been known for some time, substantial difficulties have been encountered in designing an accurate, reliable and inexpensive device for mixing the nitrogen and carbon dioxide in the correct proportions. One device which has been suggested to accomplish such mixing is in U.S. Pat. No. 4,364,493 issued to Raynes et al. However, as will become readily apparent from the descriptions which follow, Raynes et al approaches the problem in a different way and discloses an apparatus having different components operating in a entirely different manner from those of the present invention.
Due to the novel design of the gas blending component of the apparatus of the present invention, various types of gases can be precisely blended into any desired proportions. Unlike the Raynes et al device, the gas blending component of the present invention is uniquely adjustable so that through the simple manipulation thereof the proportions of the gases being mixed can be quickly and accurately varied within broad ranges.